Analog and digital electronic sensing devices are used in combination with microprocessor circuits for many applications in the automotive vehicle service industry. For example, electronic automotive vehicle wheel alignment apparatus known in the art includes multiple electronic sensing heads which are suspended from frames releasably clamped to the wheels of an automotive vehicle and which contain alignment sensor devices to provide data relating to various angles defined between the wheel plane of a selected individual wheel and the wheel plane of another selected wheel, true vertical, or an arbitrary reference.
Electronic aligners of the prior art have generally utilized special purpose microprocessors or dedicated general purpose computers to process the electronic data signals generated by the sensing heads, preferably, for display on a video monitor, to facilitate alignment of the vehicle wheels. Aligners of the prior art utilizing dedicated general purpose computers gather data from the alignment heads sequentially, one at a time, during repetitive polling cycles to update the video display as measurements are taken and adjustments are made during the course of an alignment procedure. These aligners generally suffer from slow response to alignment changes. The long data update cycle required between computations due to the sequential polling process may result in interruption or a delay of the display of wheel alignment parameters on the system's visual monitor as wheel plane relationships are changed and adjustments made in the course of performing an alignment.
Electronic automotive service equipment utilizing a dedicated general purpose computer do not allow the CPU of the computer to be utilized for other automotive vehicle service apparatus or for other business computing applications.